1. Field of the Invention
The present invention generally relates to environmental samplers, and more particularly relates to portable field samplers for microorganisms, particulate contaminates, and gasses.
2. Background Information
There are a number of situations in which it is desirable to take samples in the field of various contaminants of interest. Such samples could be taken of gases in a room or a tank. Samples could also be taken of liquids in a container or on a surface. Samples may also be taken on the surface of an object, such as a countertop, a particular food object such as an apple, or the surface of a machine or tool. At present, gas is sampled through the use of a portable test unit that uses a bulb and valves to draw air into chambers for testing. Such devices are used to test exhaust gases of boilers, for instance to test for oxygen content, carbon monoxide, and other gases. The prior art method of sampling surfaces is practiced on such diverse applications as meat carcasses in the food industry, and on the exterior surface of the NASA spacecraft as part of NASA's Planetary Protection Program.
In the case of meat carcasses, the surfaces of the carcasses are tested by a method that is aimed at standardizing a surface testing method. The method is to place a template over a section of meat carcass and then use a sponge to wipe the exposed carcass inside of the template. The wiping pattern is specified and the thought is to use a standardized swabbing method to obtain results that can be compared from one carcass to another. The problem with this is that at the microscopic level, a meat carcass is extremely rough and has cracks and crevices that are untouched by the sponge of the swab. For this reason, the swab passing over the tops of these cracks yields a very inaccurate count of the bacteria that may be present on the meat carcass.
A similar swabbing technique is also used for testing the surface of a spacecraft for exobiological contamination. However, even stainless steel has porosities in which bacteria sized organisms can lodge and be safe from a swab passing over that surface. Similarly, Formica, plastics, ceramic tile, grout, rubber, and almost anything conceivable that has grooves, cracks, and crevices at the microscopic level that makes a surface swab ineffective.
The practice of sampling for the food industry is discussed further below, but it is to be understood that the same principles apply to any type of surface sampling situation, whether sampling for radioactive particles or bacteria.
Although food borne illness is declining in some areas of the world, billions of dollars and thousands of lives are still lost annually due to food borne pathogens. Rapid bacterial detection techniques are limited in the real world by inadequate sample acquisition. Improved sampling methods are needed throughout the food industry from farm to table in order to better protect the public well-being.
Current non-destructive meat carcass sampling methods available to the industry collect bacteria located on or very near the surface. These microbes on the top surface represent only a portion of the bacteria present on meat carcass surfaces as demonstrated by significantly increased bacterial recovery using the present invention of sample collection immediately following sponge or swab sampling. Similar circumstances likely apply to macro or microscopically porous food preparation surfaces, such as cutting boards, conveyor belts, and some grinding or processing bins and equipment. In addition, cross-contamination between multiple sampling areas may be significant with sponge sampling. Minute hydrophobic surface cracks and crevices on carcasses may provide adequate protection for microbes to escape during surface anti-microbial solution treatments and during collection with sponge or swab surface sampling procedures.
An object of the present invention is to provide a sampling means comparable to the excision method, but that does not destroy the sampling surface. The microbial collection and concentration device of the present invention meets these needs.
In addition, the present invention has been developed with a focus on improved food safety through better sample collection from meat carcasses, and from food preparation surfaces and containers.
Another object of the present invention is to provide a collection/capturing means that can non-destructively sample/collect bacteria from items such as meat carcass in a more proficient means, especially out of surface cracks and indentations.
Another object of the present invention is to provide an application that can be utilized by a single person and thus reduce labor costs.
Additional objects, advantages and novel features of the invention will be set forth in part in the description which follows and in part will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.